1. Technical Field
This invention relates to adjustable arc of coverage spray nozzles, and more particularly, to such nozzles which have preset spray ranges, and in which an upstream throttling valve is proportionally mechanically coupled to the arc of coverage adjustment so that a substantially constant precipitation rate can be selected and provided as the arc of coverage is adjusted. The invention also relates to sprinkler systems including a plurality of such nozzles with different spray ranges.
2. Relevant Prior Art
Sprinkler nozzles are known which have an adjustable arc of coverage, e.g., as shown in Hunter U.S. Pat. No. 4,579,285, and in my U.S. Pat. No. 5,588,594.
My U.S. patent application Ser. No. 10/100,259 entitled SPRAYNOZZLE WITH ADJUSTABLE ARC SPRAY ELEVATION ANGLE AND FLOW, filed Mar. 15, 2002 discloses an adjustable range and arc of coverage nozzle having an adjustable arcuate spray slot in which the arc setting mechanism is linked to an upstream throttling valve to proportionally control the flow to the spray slot as the arc of spray coverage is increased or decreased. Although other arc-settable spray nozzles that have adjustable upstream throttling valves are also known, the upstream throttling valve areas of these are not preset at the factory during assembly to provide the correct flow rate for the desired range of coverage while still maintaining the same larger adjustable slot width, and if adjusted, are not designed to provide proportionally increasing area openings as the arc of coverage is increased for substantially uniform precipitation independent of the arc of coverage setting.
The short range adjustable arc nozzles which are now on the market have adjustable arcuate slot orifices that are quite thin e.g., less than 0.030 inch, to reduce the flow rates for the shorter ranges of coverage such as 8 feet. These very thin slots are easily clogged and require fin filters having correspondingly small openings, which themselves are easily clogged.
There is accordingly a need for an improved adjustable arcuate slot nozzle in which an upstream proportional flow rate adjusting valve and an arc of coverage adjustment mechanism are coupled so that a substantially constant pre-settable precipitation rate is obtained for different arcs of coverage when the desired flow rate is less than what the adjustable arcuate slot alone provides. The present invention seeks to address this need, in addition to having the nozzles preset at the factory to provide selected shorter ranges of coverage such as 8, 10, 12, and 15 feet.
According to this invention, a simple arc-settable spray nozzle may have a relatively large adjustable arc spray slot width (e.g., at least 0.030 in.) for even short range nozzle configurations. Also, by proportionally throttling the flow upstream of the adjustable arc slot, the width of the open area of the arcuate slot can be substantially constant and uniform, independent of the arc setting. The upstream valve can be formed of one or more relatively large axial-width openings which concentrate the flow area in larger size grooves of a selected shape to proportionately open or close the flow area as the upstream throttling valve member is moved axially during setting of the desired arc of coverage. Since the upstream flow is concentrated into a small number of openings or grooves while still providing significant throttling, the adjustable arcuate spray slot may now have a greater opening size while still providing the desired lower flow rate for the short range nozzles.
As the arc opening of the adjustable arcuate spray slot is varied by rotation of a spray nozzle deflector and flow control member, a coupled throttling valve element varies the area of the upstream openings. Due to the configuration of the upstream openings, and other parts, the throttling is proportional to the arc opening of the arcuate spray slot.
Also, a pressure compensating configuration is disclosed in which one member of the upstream throttling valve is made of a flexible material so that it is pressure responsive. Thus, if the inlet pressure increases, the throttling valve flow area is reduced to compensate for the pressure change.
It is accordingly an object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle.
It is another object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle in which an upstream flow rate adjusting valve provides proportional adjustment to match the rotational and axial movement of the coupled arc of coverage adjustment mechanism so that a substantially constant precipitation rate is obtained for different arcs of coverage, even when the flow rate is preadjusted to be less than would flow from the adjustable arcuate slot alone to provide for the same precipitation rate.
It is yet another object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle in which an upstream flow rate adjusting valve and an arc of coverage adjustment mechanism can be pre-set, for example, during assembly at the factory, to provide a substantially constant pre-selected precipitation rate for different arcs of coverage, and in which different maximum-flow settings of the upstream flow rate adjusting valve are provided for different ranges of coverage.
It is a further object of the present invention to provide an improved adjustable arc of coverage sprinkler nozzle with a coupled upstream flow rate adjusting valve and different configurations for different ranges of coverage in which the short range valve configurations are less subject to contamination by dirt than in conventional nozzles.
Another object of the invention is to provide a fixed range spray nozzle in which the exit elevation angle of the nozzle flow control deflector determines the spray range and the precipitation rate may be adjusted with an upstream flow control valve whose flow rate is proportionally controlled by a mechanical linkage with the arc of coverage setting mechanism for the adjustable arc of coverage slot.
So that the nozzle can be used for different spray ranges as part of a sprinkler system, the flow control mechanism includes an interchangeable deflector that determines the range, and the maximum flow rate for an upstream throttling valve is preset to match the selected range by pre-positioning a movable valve member relative to a plurality of axial outlet orifice slots which concentrate the flow out of the throttling valve, and are configured to provide the required proportional flow adjustability. This construction allows use of outlet slots that are large enough to minimize the risk of obstruction by dirt for even the smallest range nozzle.
In a second embodiment, the flow throttling valve body is formed by a resilient diaphragm that includes one or more axial outlet orifice slots. The diaphragm includes a folded area that deflects in response to increased inlet water pressure, and thereby reduces the area of the outlet opening. By properly selecting the thickness and rigidity of the folded area, the changes in the size of the outlet opening can compensate for pressure variations and thus help keep the flow more constant at elevated inlet pressures.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.